class X:
    def info(self):
        print("X.info")
        super().info()


class Y:
    def info(self):
        print("Y.info")
        super().info()


class Z:
    def info(self):
        print("Z.info")


class SubItem(X, Y, Z):
    pass


subItem = SubItem()
subItem.info()
# X.info
# Y.info
# Z.info

# [<class '__main__.SubItem'>, <class '__main__.X'>, <class '__main__.Y'>, <class '__main__.Z'>, <class 'object'>]
print(SubItem.mro())

"""
SubItem(X, Y , Z):
    pass

形成了一个 mro ，就是 X Y Z
这个时候，X.super() 就是 Y
Y.super() 就是 Z
Z.super() 就是 object
所以显示：X.info Y.info Z.info
"""
